Melt the Stork butter in a pan on a very low temperate. Set aside. >Do not allow it to boil/burn! Place the two types of sugar into a large mixing bowl and stir together until they're evenly mixed.
Add the melted butter to the sugar and whisk until fully combined>Takes about 15 seconds of vigorous whisking. The sugar should look a little less grainy when you're done! Add the whole egg and egg yolk and whisk in until fully combined>Balloon whisk for about 10 seconds Take 4 of your "Oreos" and crush into tiny pieces like the picture>I put them in a bowl, break them up a bit with my hands and then use the end of rolling pin to bash them into small pieces. You could also seal them up in a sandwich bag and do the same. Put the crushed Oreos from the step above, baking powder, baking soda and flour into a bowl and stir together.
Add half the flour/oreo mix to the butter/sugar egg mix and whisk in until combined.>I recommend using a wooden spoon/ordinary spoon for this, not a whisk, otherwise it all gets stuck in the whisk and its annoying! Add the other half of the flour/oreo mix and whisk in until fully combined.>There should be no white bits of flour left in the mix at this stage. If there is, keep whisking! Take another 2 oreos and break into larger chunks. Place into the cookie dough and mix together.
Cover the mixing bowl with cling film and place into the fridge for at least 1 hr>Don't worry if its looking quite runny at this stage – it firms up loads in the fridge! Overnight is great if possible.>You can put it in the freezer rather than the fridge if that's easier, reducing the chill time to 45 mins.